How do you vacuum oil out of an engine?

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How do you vacuum oil out of an engine?

While many do-it-yourselfers love to change their own oil, they hate sliding under the car and getting their hands covered with grimy, black oil. Using an inexpensive tool called an oil extractor makes the job much easier and cuts the time in half.

The oil extractor works by sucking the oil from the crankcase through a thin tube inserted in the dipstick opening. A handle is pumped repeatedly to create a vacuum that pulls the hot oil into an easy-to-carry container. It can then be taken to an auto parts store for recycling.

Two Cars, Two Tests
To test this procedure we changed the oil on a 2005 Lotus Elise and a 2007 Honda Fit Sport. We had great results in both cases and believe that this is an attractive option for car owners who like to do oil changes themselves. As one user commented, “If you can cook yourself dinner, you can change your own oil. The most difficult part is getting underneath the car to drain the old oil. Now that is no longer an issue!”

Changing your own oil, whether “top-down” or the old-fashioned oil change from under the engine, is a great way to save money. Recently, we went to a fast oil change chain outlet and it cost $40, and they tried hard to upsell us an additional $60 in services. The oil filter and 4 quarts of oil costs as little as $23.

Performing a Top-Down Change
The Lotus Elise belongs to Edmunds Associate Editor Mark Takahashi, who had recently driven it hard at a track day. Therefore, he wanted an oil change only and would continue to use the same filter until his next oil change.

How do you vacuum oil out of an engine?

Takahashi said that he has been charged as much as $170 for an oil change. “In order to do a conventional oil change, the car must be elevated,” Takahashi said. “Not just because of its low ride height but because the entire underside of the car is flat to maximize aerodynamic performance. Accessing the drain plug and filter requires you to unbolt the undertray. In the absence of a lift, ramps are the only alternative. Even then, the ramps must be of the low-profile variety in order to avoid destroying the fiberglass bodywork of the chin spoiler.”

We found a nice shade tree on a Santa Monica side street, parked the Lotus and went to work. We opened the cover of the midengine car and inserted the thin flexible tube down through the dipstick opening. We connected the other end to the extractor, pumped the handle about 15 times and the hot oil began flowing. It took about 8 minutes to drain the engine, which holds 5 quarts.

The oil extractor we used, a $63, 5-quart Moeller Fluid Extractor, has an automatic shut-off. Since Takahashi had topped off the engine, he had more than 5 quarts, causing the extractor to stop draining. We had to pour some oil out into another container and continue the procedure, a minor delay. After refilling the engine with new oil and double-checking all our work, we finished the whole job in about 20 minutes.

It was then easy to put the rubber stopper into the oil extractor, take the container to a local auto parts store and have them empty the old oil into their recycle bin.

Can You Get All the Oil Out?
While researching this story, we found that some people have posted Internet messages saying they are doubtful of this method. Wouldn’t there be some oil left in the lowest part of the oil pan? And wouldn’t this oil contain harmful sludge? Sludge is actually an extremely harmful gelling that occurs when water is combined with oil. This has little to do with a successful oil change.

Skeptics were probably intending to say they wanted all particulate matter removed along with the old oil. If the car has been warmed up before the oil change, as recommended, any particulate matter would flow out with the oil.

We decided to do an oil change on a Honda Fit belonging to Consumer Advice Editor Philip Reed to investigate this further. We sucked out the 3.8 quarts of oil and then removed the oil drain plug to see how much more flowed out. We were pleased to see that it was less than 3 tablespoons. This oil didn’t appear to be any more contaminated than what had been sucked out by the extractor. We also unscrewed the filter and found it still contained about a quarter cup of oil.

Are There Drawbacks?
An oil extractor is perfect for anyone with a car that has the oil filter located on the top of the engine, such as certain BMW and Mercedes models. In these cases, there is no need to get under the car at all.

For all other cars, it is still necessary to remove the oil filter, in which case you will probably have to slide underneath the vehicle. Often this means jacking up the car and leaving it supported on a jack stand for safety reasons. Still, the extractor eliminates the difficulty of wrestling with a stubborn drain plug bolt while in an awkward position under the car. Also, anyone who has drained oil knows that removing the drain plug often means having hot oil gush onto your hand.

What To Look for in an Oil Extractor

Buy an oil extractor with a large enough reservoir to hold the entire contents of your engine’s crankcase (our model held only 5 quarts, not large enough for many vehicles).
Some models not only suck the oil out, but they can then pump it out of the reservoir into recycling containers, a handy feature.
Hand pump models seem to create plenty of suction for passenger vehicles, so electric pumps or vacuum-powered extractors may not be necessary.
Look for a model that makes it easy to pour the used oil into recycling containers.

A Few Oil Extractor Tips

While doing a top-down oil change greatly reduces the handling and possible spilling of old hot oil, some oil will drip out of the tubing after it is removed from the dipstick opening. Be ready with a rag or old newspapers to catch these drips. Also, never let oil drip on your car’s finish.
We found that with the Lotus, the dipstick was slanted so that when the tube hit the bottom of the oil pan it didn’t stop but continued feeding in through the opening. We solved this by holding the dipstick next to the tube to estimate the correct insertion depth. With the Honda, it was clear when we had the tube inserted the right amount since it hit the bottom and stopped.
Remember to keep records of when you change the oil. If you have a maintenance minder, such as that used in the Honda Fit, remember to reset it so it will remind you the next time an oil change is needed.
Consider taking a sample and having your engine oil analyzed to fine-tune your oil change intervals